Manufacturing method of a semiconductor device incorporating a passive element and a redistribution board

ABSTRACT

A manufacturing method of a semiconductor device incorporating a passive element includes the steps as follows: a redistribution board forming step forms a redistribution board incorporating the passive element on a base board; a semiconductor element mounting step mounts at least one semiconductor element formed on an opposite side surface of the redistribution board with regard to the base board; a base board separating step separates the base board from the redistribution board and exposes the other surface of the redistribution board; a redistribution board mounting step mounts the redistribution board on a package board via electrode pads exposed from the other surface of the redistribution board.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention generally relates to a semiconductor devicemounting a logic device and the like that requires high-speedprocessing, and more particularly, to a semiconductor deviceincorporating a passive element such as a capacitor in a package.

[0003] 2. Description of the Related Art

[0004] Generally, in a semiconductor device mounting an LSI thatoperates at high speed, a bypass condenser is incorporated in a packageboard in order to prevent variation of power supply voltage andmalfunction due to high-frequency noise, and to secure stable operationin a high-speed operation area.

[0005] The bypass condenser is mounted on the package board as adifferent chip part from a semiconductor element that is mounted on thepackage board by flip chip mounting (FC mounting). In order to make thebypass condenser function effectively, it is necessary to place thebypass condenser near the semiconductor element. In many cases, thebypass condenser is placed at an opposite side of the package board withregard to the part on which the semiconductor element is mounted.

[0006] However, it is difficult to secure an area for mounting thebypass condenser on the package board close to the part where thesemiconductor elements are mounted when mounting terminals for manysignals and mounting terminals for power source and grounding areplaced, or when a plurality of semiconductor elements are mounted on thepackage board as a system-in package. Accordingly, a structure isproposed in which the bypass condenser is placed inside the packageboard.

[0007] For example, an attempt has been made to incorporate the bypasscondenser in the package board such as a glass ceramic board. However, ayield ratio may be reduced and an increase in costs may be caused sincethe number of wiring layers increases compared with a current situationand it is necessary to introduce a special material and a process.

[0008] As a method to solve this problem, it is conceived that aconventional board is used for the package board and only thesemiconductor element requiring the bypass condenser is mounted on thepackage board via a redistribution board incorporating the capacitor.

[0009] However, board technology (wiring, multilayer, via formingtechnology) is required that can correspond to a minute electrode pad ofthe semiconductor element and a pitch between the electrode pads.Additionally, it is necessary to form vias so that a circuit on theredistribution board passes through to a reverse side of theredistribution board. Thus, it is substantially difficult to furtherreduce costs as achieving performance of a device. As a matter ofcourse, it is necessary to structure the redistribution board as simplyas possible in order to satisfy electric properties required by thesemiconductor element mounted and to reduce costs.

[0010] However, when a thickness of the redistribution board becomesthin by simplifying the structure of the redistribution board, rigidityof the redistribution board is decreased. Thus, the redistribution boardmay be deformed or damaged easily in a manufacturing process of thesemiconductor device.

SUMMARY OF THE INVENTION

[0011] It is a general object of the present invention to provide animproved and useful manufacturing method of a semiconductor device and aredistribution board in which the above-mentioned problems areeliminated.

[0012] A more specific object of the present invention is to provide amanufacturing method of a semiconductor device packaging thesemiconductor element and a redistribution board incorporating a passiveelement such as the bypass condenser and a preferred redistributionboard for such a semiconductor device in which the above-mentionedproblems are eliminated.

[0013] In order to achieve the above-mentioned objects, there isprovided according to one aspect of the present invention amanufacturing method of a semiconductor device incorporating a passiveelement comprising the steps of: a redistribution board forming stepforming a redistribution board incorporating the passive element on abase board; a semiconductor element mounting step mounting at least onesemiconductor element on an opposite side surface of the redistributionboard formed on the base board with regard to the base board; a baseboard separating step separating the base board from the redistributionboard and exposing the other surface of the redistribution board; and aredistribution board mounting step mounting the redistribution board ona package board via electrode pads exposed from the other surface of theredistribution board.

[0014] According to the above-mentioned aspect of the present invention,the redistribution board is fixed to the bas board until thesemiconductor element is mounted on the redistribution board, thus thebase board reinforces the redistribution board. Additionally, thesemiconductor element functions to reinforce the redistribution boardafter the base board is removed. Thus, the redistribution board isprevented from being deformed or damaged since the redistribution boardis always reinforced by the base board or the semiconductor element andnot handled by itself.

[0015] The object described above is also achieved, according to anotheraspect of the present invention, by the manufacturing method of thesemiconductor device mentioned above, wherein the semiconductor elementmounting step includes a step of filling between the redistributionboard and the semiconductor element with an under fill material.

[0016] According to the above-mentioned aspect of the present invention,the redistribution board is further reinforced by the under fillmaterial.

[0017] The object described above is also achieved, according to anotheraspect of the present invention, by a manufacturing method of asemiconductor device incorporating a passive element comprising thesteps of: a redistribution board forming step forming a redistributionboard incorporating the passive element on a base board; aredistribution board mounting step mounting the redistribution boardformed on the base board on a package board via electrode pads exposedfrom the other surface of the redistribution board; a base boardseparating step separating the base board from the redistribution boardand exposing the other surface of the redistribution board; and asemiconductor element mounting step mounting at least one semiconductorelement on the redistribution board via electrode pads exposed from theother surface of the redistribution board.

[0018] According to the above-mentioned aspect of the present invention,the redistribution board is fixed to the base board until theredistribution board is mounted on the package board, thus the baseboard reinforces the redistribution board. Additionally, the packageboard functions to reinforce the redistribution board after the baseboard is removed. Thus, the redistribution board is prevented from beingdeformed or damaged since the redistribution board is always reinforcedby the base board or the package board and not handled by itself.

[0019] The object described above is also achieved, according to anotheraspect of the present invention, by the manufacturing method of thesemiconductor device mentioned above, wherein the redistribution boardmounting step includes a step of filling between the redistributionboard and the package board with the under fill material.

[0020] According to the above-mentioned aspect of the present invention,the redistribution board is further reinforced.

[0021] The object described above is also achieved, according to anotheraspect of the present invention, by the manufacturing method of thesemiconductor device, wherein the base board is made of a silicon wafer,a plurality of the redistribution boards are integrally formed on thesilicon wafer, and the redistribution boards are individualized afterthe base board removing step.

[0022] According to the above-mentioned aspect of the present invention,it is possible to handle a plurality of the redistribution boardsintegrally and to simplify the semiconductor production process.

[0023] The object described above is also achieved, according to anotheraspect of the present invention, by a manufacturing method of asemiconductor device incorporating a passive element comprising: aredistribution board forming step forming a redistribution boardincorporating the passive element on a base board; a base boardseparating step separating the base board from the redistribution board;a semiconductor element mounting step mounting at least onesemiconductor element on the redistribution board via electrode padsformed on a surface of the redistribution board; and a redistributionboard mounting step mounting the redistribution board on a package boardvia electrode pads formed on the other surface of the redistributionboard.

[0024] According to the above-mentioned aspect of the present invention,flexibility of the semiconductor production process is increased sincethe mounting process can be started on either surface of theredistribution board.

[0025] The object described above is also achieved, according to anotheraspect of the present invention, by the manufacturing method of thesemiconductor device mentioned above, wherein the redistribution boardforming step includes a step of forming columnar metal members onelectrode pads of the redistribution board formed on an opposite side ofthe base board, and a step of filling between the columnar metal memberswith insulating resin.

[0026] According to the above-mentioned aspect of the present invention,it is possible to prevent the redistribution board from being deformedor damaged since the redistribution board is reinforced by theinsulating resin.

[0027] The object described above is also achieved, according to anotheraspect of the present invention, by the manufacturing method of thesemiconductor device mentioned above, wherein the redistribution boardforming step includes a step of forming columnar metal members onelectrode pads of the redistribution board formed on an opposite side ofthe base board, and a step of filling between the columnar metal memberswith insulating resin.

[0028] According to the above-mentioned aspect of the present invention,it is possible to prevent the redistribution board from being deformedor damaged in the manufacturing process of the semiconductor since theinsulating resin reinforces the redistribution board.

[0029] The object described above is also achieved, according to anotheraspect of the present invention, by the redistribution board mentionedabove, wherein the columnar metal members are made of a copper platedlayer deposited in a columnar structure.

[0030] According to the above-mentioned aspect of the present invention,it is possible to deposit the copper plating in a columnar structure bya lithography technology using photoresist so as to form the columnarmetal members easily on the electrode pads.

[0031] The object described above is also achieved, according to anotheraspect of the present invention, by the redistribution board mentionedabove, wherein the columnar metal members are made of gold wire andconnected with the electrode pads by a wire bonding method.

[0032] According to the above-mentioned aspect of the present invention,it is possible to form the columnar metal members easily by bonding thegold wire with the electrode pads.

[0033] The object described above is also achieved, according to anotheraspect of the present invention, by a manufacturing method of aredistribution board incorporating a passive element comprising thesteps of: a step of forming a copper sputter film on a ceramic board; aredistribution board forming step forming the redistribution boardincorporating the passive element on the copper sputter film; a baseboard separating step exfoliating and separating the ceramic board fromthe copper sputter film; and a step of removing the copper sputter filmby etching and exposing electrodes of the redistribution board.

[0034] According to the above-mentioned aspect of the present invention,it is possible to exfoliate the ceramic board as the base board from theredistribution board including the copper sputter film easily since theadhesion between the copper sputter film and the ceramic board is weak.The redistribution board can be formed by removing the copper sputterfilm after the ceramic board is exfoliated.

[0035] Other objects, features and advantages of the present inventionwill become more apparent from the following detailed description whenread in conjunction with the following drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0036]FIG. 1 is a cross sectional view of a semiconductor deviceaccording to a first embodiment of the present invention;

[0037]FIGS. 2A and 2B are cross sectional views for explaining astructure of a redistribution board and manufacturing process;

[0038]FIGS. 3A, 3B and 3C are cross sectional views for explaining themanufacturing process of the semiconductor device shown in FIG. 1;

[0039]FIG. 4 is a flow chart of the manufacturing process of thesemiconductor device shown in FIG. 1;

[0040]FIG. 5 is a cross sectional view of a semiconductor deviceaccording to a second embodiment of the present invention;

[0041]FIGS. 6A, 6B and 6C are cross sectional views for explainingmanufacturing process of the semiconductor device shown in FIG. 5;

[0042]FIG. 7 is a flow chart of the manufacturing process of thesemiconductor device shown in FIG. 5;

[0043]FIGS. 8A, 8B, 8C and 8D are cross sectional views for explaining amanufacturing method of a semiconductor device according to a thirdembodiment of the present invention;

[0044]FIG. 9 is a cross sectional view of a semiconductor deviceaccording to a fourth embodiment of the present invention;

[0045]FIGS. 10A, 10B, 10C and 10D are cross sectional views forexplaining the manufacturing process of the redistribution board shownin FIG. 9;

[0046]FIG. 11 is an enlarged view of a part surrounded by a broken linein FIG. 9;

[0047]FIG. 12 is a cross sectional view of a semiconductor deviceaccording to a fifth embodiment of the present invention;

[0048]FIG. 13 is a cross sectional view of a semiconductor deviceaccording to a sixth embodiment of the present invention;

[0049]FIGS. 14A and 14B are cross sectional views for explaining themanufacturing process of the redistribution board shown in FIG. 13; and

[0050]FIG. 15 is a cross sectional view of a semiconductor deviceaccording to a seventh embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0051] Next, a description will be given of embodiments of the presentinvention.

[0052]FIG. 1 is a cross sectional view of a semiconductor deviceaccording to a first embodiment of the present invention. Thesemiconductor device according to the first embodiment of the presentinvention includes a package board 2, a redistribution board 4 connectedwith the package board 2, a first semiconductor element 6 and a secondsemiconductor element 8. The first and second semiconductor elements 6and 8 are mounted on the redistribution board 4. Further, the number ofthe semiconductor elements mounted on the redistribution board 4 may beone, or three or more. Additionally, in this embodiment, a heat spreader10 is fixed to back surfaces of the first and second semiconductorelements by an adhesive 12. The heat spreader 10 functions so as toaccelerate heat dissipation from the semiconductor elements 6 and 8.However, the heat spreader 10 is not always necessary and provided incase of need.

[0053] The package board 2 is structured by a glass ceramic board, analumina board or a built-up board. On a top surface 2 a of the packageboard 2, electrode pads connected with solder bumps 14 are formed. On anunder surface 2 b of the package board 2, electrode pads are formedwhere solder balls 16 are formed as external terminals. The packageboard 2 is a multilayered structure. The electrode pads on the topsurface 2 a are electrically connected with the corresponding electrodepads on the under surface 2 b by vias or the like which penetratethrough layers.

[0054] As shown in FIG. 1, the redistribution board 4 has a multilayerdstructure. Built-in capacitors 18 that function as the bypass condensersare formed inside the redistribution board 4. Electrode pads formed by afirst electric conductive layer are exposed from an under surface 4 b ofthe redistribution board 4 and connected with the correspondingelectrode pads of the package board 2 via the solder bumps 14.Additionally, electrode pads formed by a fourth electric conductor areexposed from a top surface 4 a of the redistribution board 4 and usingthese electrode pads, the first and second semiconductor elements 6 and8 are mounted on the redistribution board 4 by flip chip mounting.

[0055]FIGS. 2A and 2B respectively are cross sectional views forexplaining the structure of the redistribution board 4 and manufacturingprocess. First, as shown in FIG. 2A, electrode pads are formed byforming a pattern of platinum thin film as the first electric conductor22 on a base board 20 such as a silicon board or the like. Next, a BSTfilm (barium/strontium/titanium filter) having a high dielectricconstant is formed as a first insulating layer 24. Then, after formingfirst vias 26 at necessary positions, electrode pads are formed byforming a pattern of the platinum thin film as a second electricconductive layer 28 on the first insulating layer 24. Among theelectrode pads formed on both sides of the first insulating layer 24,pairs of the electrode pads connected by the first vias 26 function aselectrically conductive parts. On the other hand, pairs of the electrodepads facing without the first via 26 function as capacitors since theBST film having the high dielectric constant stands between. Thesecapacitors become the incorporated capacitors 18 and function as thebypass condensers when incorporated in the semiconductor device.

[0056] Next, as shown in FIG. 2B, a second insulating layer 30 is formedon the second electric conductive layer 28. A copper wiring pattern isformed on the second insulating layer 30 as a third electric conductivelayer 32. The second insulating layer 30 is formed by polyimide, BCBfilm or the like. Viaholes are formed in corresponding positions of theelectrode pads of the second electric conductive layer 28. A thirdelectric conductive layer 32 is formed by copper (Cu) plating, forexample, and second vias 34 are formed in the viaholes. Thus, the copperwiring pattern 32 formed on the second insulating layer 30 and theplatinum thin film wiring pattern formed as the second electricconductive layer 28 are electrically connected by the second vias 34.The copper wiring pattern as the third electric conductive layer 32becomes a wiring pattern for redistribution.

[0057] Next, a third insulating layer 36 is formed on the third electricconductive layer 32. A copper wiring pattern is formed on the thirdinsulating layer 36 as a fourth electric conductive layer 40. The thirdinsulating layer 36 is formed by polyimide, BCB film or the like.Viaholes are formed in corresponding positions of the copper wiringpattern of the third electric conductive layer 32. A fourth electricconductive layer 40 is formed by copper (Cu) plating, for example, andthird vias 38 are formed in the viaholes. Thus, the copper wiring formedon the second insulating layer 30 and the copper wiring pattern formedon the third insulating layer 36 are electrically connected by the thirdvias 38. The copper wiring pattern as the fourth electric conductivelayer 40 is formed as the electrode pads. On these electrode pads, theabove-described first and second semiconductor elements 6 and 8 aremounted by flip chip mounting.

[0058] When forming the above-described third and fourth electricconductive layers 32 and 40 by copper plating, it is desirable to formsputter thin films of such as Ti, Cr, W or the like prior to the copperplating in order to secure adhesion with the respective insulatinglayers below the third and fourth electric conductive layers 32 and 40,and to enable electrolytic plating. Additionally, a thickness of thesecond and third insulating layers 30 and 36 is 2 μm to 10 μm. Athickness of the copper wiring patterns 32 and 40 is approximatelyseveral micrometers. In addition, the wiring pattern as the fourthelectric conductive layer 40 corresponds to the electrode pads mountingthe semiconductor elements 6 and 8 by flip chip packaging. Thus, it ispreferable to perform barrier metal plating such as Ni plating or thelike and plating of such as Au, Pd, Sn or the like to the fourthelectric conductive layer.

[0059] As shown in FIG. 2B, the redistribution board 4 is formed on thebase board 20. However, the base board 20 is removed when manufacturingthe semiconductor device using the redistribution board 4. Since theredistribution board 4 is thin, it may be easily deformed or damagedwhen separated from the base board 20.

[0060] Further, the above-described redistribution board 4 may bemanufactured by a method proposed in Japanese Laid-Open PatentApplication No. 2001-274036.

[0061] Next, a description will be given of the manufacturing process ofthe semiconductor device according to the present invention withreference to FIGS. 3A, 3B, 3C and 4.

[0062] First, as shown in a flow chart of FIG. 4, the redistributionboard 4 is prepared. In step S1, the first electric conductive layer 22formed by a platinum thin film is formed on a silicon wafer referred toas the base board 20. Next, in step S2, the BST film as the firstinsulating layer 24 is formed on the first electric conductive layer 22.Then, in step S3, the second electric conductive layer 28 formed by theplatinum film is formed on the BST film.

[0063] Next, in step S4, a polyimide film as the second insulating layer30 is formed on the second electric conductive layer 28. In step S5, thethird electric conductive layer 32 made of copper plating is formed onthe polyimide film. In step S6, a polyimide film as the third insulatinglayer 36 is formed on the third electric conductive layer 32. In stepS7, the fourth electric conductive layer 40 made of copper plating isformed on the polyimide film.

[0064] The steps S1 through S7 are the processes for preparing theredistribution board 4. Further, by repeating steps S5 and S6, thenumber of layers of the redistribution board 4 can be further increased.

[0065] When the preparation of the redistribution board 4 is completed,a process is performed for mounting the semiconductor elements 6 and 8on the redistribution board 4 by flip chip packaging. That is, in stepS8, Ni plating is performed as the barrier metal on the electrode padsof the fourth electric conductive layer 40 of the redistribution board4, and another plating of such as Au, Pd, Sn or the like is performedthereafter. Then, in step S9, the semiconductor elements 6 and 8 towhich solder bumps are previously formed are mounted on the fourthelectric conductive layer 40 of the redistribution board 4 by flip chipmounting. Instead of solder bonding, Au—Sn bonding may be employed byforming Au stud bumps to the semiconductor elements 6 and 8, andperforming tin-plating on the redistribution board 4 side.

[0066] Next, in step S10, an under fill material 44 fills between theredistribution board 4 and the semiconductor elements 6 and 8,respectively so as to secure reliability of the flip chip mounting. Inthis embodiment, the semiconductor elements 6 and 8 are mounted on theredistribution board 4 by flip chip mounting. However, the number of thesemiconductor elements mounted may alternately be one, or three or more.

[0067] As shown in FIG. 3A, the redistribution board 4 assumes a statewhere the first and second semiconductor elements 6 and 8 are mountedafter the above-described processes. The steps S1 through S10 areperformed while the redistribution board 4 is formed on the base board20. Accordingly, the base board 20 functions to reinforce the thinredistribution board 4. Thus, it is possible to perform flip chipmounting of the semiconductor elements 6 and 8 easily, and to preventthe redistribution board 4 from being deformed or damaged.

[0068] In step 11, the base board 20 made of a silicon board is removedafter the semiconductor elements 6 and 8 are mounted on theredistribution board 4 and fixed by the under fill material 44. The baseboard 20 can be removed by etching or back grind (grinding). The etchingand the back grind may be used together. By removing the base board 20,the first electric conductive layer 40 is exposed from a surface of theredistribution board 4 as shown in FIG. 3B.

[0069] Further, although the base board 20 is removed, since thesemiconductor elements 6 and 8 are fixed on the opposite side of theredistribution board 4 by the under fill material 44, the semiconductorelements 6 and 8 function to reinforce the redistribution board 4 so asto prevent the redistribution board 4 from being deformed or damaged.

[0070] Next, in step 12, solder bumps are formed on the electrode padsmade of the first electric conductive layer 22 of the redistributionboard 4. The redistribution board 4 is mounted on the package board 2made of such as glass ceramic board, built-up board or the like. Then,the reliability of the mounting is secured by filling an under fillmaterial 46 between the redistribution board 4 and the package board 2.Then, in step S13, the heat spreader 10 is fixed to the semiconductorelements 6 and 8, respectively, via the adhesive 12. Last, in step S14,solder balls 16 are formed as external terminals to the electrode padsprovided on a bottom face side of the package board 2, and thesemiconductor device shown in FIG. 3C is accomplished.

[0071] When it is not necessary to provide the heat spreader 10 in stepS13, step S13 may be skipped to advance to step 14. Additionally, withregard to steps S13 and S14, either step may be performed first.

[0072] Further, in the above embodiment, the silicon wafer is used forthe base board 20. However, when the base board 20 is in a state of awafer, it is also possible to form a plurality of redistribution boards4 on the wafer. In this case, it is preferable that a process ofindividualizing such as dicing or the like be performed after theprocess of step S7 ends, or after the process of either step S9 or S10ends.

[0073] Next, a description will be given of a second embodiment of thepresent invention with reference to FIG. 5. FIG. 5 is a cross sectionalview of a semiconductor device according to the second embodiment of thepresent invention. In FIG. 5, those components which are the same asthose corresponding components in FIG. 1 are designated by the samereference numerals, and a description thereof will be omitted.

[0074] The semiconductor device according to the second embodiment ofthe present invention uses the same components as the semiconductordevice according to the first embodiment of the present invention.However, there is a difference between the semiconductor deviceaccording to the second embodiment of the present invention and thesemiconductor device according to the first embodiment of the presentinvention in that the redistribution board 4 is placed upside down. Thatis, the electrode pads made of the fourth electric conductive layer 40of the redistribution board 4 are connected with the electrode pads ofthe package board 2. The semiconductor elements 6 and 8 are mounted onthe electrode pads made of the first electric conductive layer 22.

[0075]FIGS. 6A, 6B and 6C are cross sectional views for explaining themanufacturing process of the semiconductor device shown in FIG. 5. FIG.7 is a flow chart of the manufacturing process of the semiconductordevice shown in FIG. 5.

[0076] In FIG. 7, steps S21 through S27 are processes for forming theredistribution board 4 the same as the processes of steps S1 through S7in FIG. 4. In this embodiment, after the redistribution board 4 isformed on the base board 20, a preprocessing is performed for mountingthe redistribution board 4 on the package board in step S28. That is,when the redistribution board 4 is mounted by the solder bonding, thesolder bumps are formed to the package board. Alternatively, when theredistribution board 4 is mounted by the Au—Sn bonding, Au stud bumpsare formed to the electrode pads of the package board 2 and tin-platingprocess is performed to the electrode pads of the redistribution board4.

[0077] Next, in step S29, as shown in FIG. 6A, the redistribution board4 is mounted on the package board 2. In step S30, the under fillmaterial 46 is injected between the redistribution board 4 and thepackage board 2. Thereafter, in step S31, as shown in FIG. 6B, the baseboard 20 is removed. The base board 20 is removed by the same method asthe above-described first embodiment.

[0078] As described above, in this embodiment, the redistribution board4 is mounted on the package board 2 before the base board 20 is removedfrom the redistribution board 4. Thus, the redistribution board 4 isalways reinforced by the base board 20 or the package board 2.Therefore, the deformation of or the damage to the redistribution board4 due to the redistribution board 4 being by itself without anyreinforcement can be prevented.

[0079] When the base board 20 is removed in step S31, the first electricconductive layer 22 is exposed from a surface of the redistributionboard 4. Then, in step S32, the semiconductor elements 6 and 8 aremounted on the redistribution board 4 by flip chip mounting, and underfill material 44 is filled between the semiconductor elements 6 and 8and the redistribution board 4, respectively. In step S33, as in thefirst embodiment, the heat spreader 10 is connected with thesemiconductor elements 6 and 8 by the adhesive 12. In step S34, solderballs 16 are formed on the electrode pads on the bottom side surface ofthe package board 2, and the semiconductor device shown in FIGS. 5 and6C is completed.

[0080] Next, a description will be given of a third embodiment of thepresent invention with reference to FIGS. 8A, 8B, 8C and 8D. Thesemiconductor device of the third embodiment of the present inventionhas the same structure as the semiconductor device of theabove-described first or second embodiment. However, the semiconductordevice of the third embodiment of the present invention differs from thesemiconductor device of the first or second embodiment in themanufacturing process.

[0081] In the third embodiment of the present invention, as shown inFIG. 8A, the redistribution board 4 is formed on the base board 20.Thereafter, as shown in FIG. 8B, the base board 20 is separated orremoved from the redistribution board 4. Thereafter, the redistributionboard 4 is bonded to the semiconductor elements 6 and 8 and the packageboard 2. As shown in FIG. 8C, the semiconductor elements 6 and 8 may bemounted on the redistribution board 4 previous to the package board 2.Or, as shown in FIG. 8D, the package board 2 may be mounted on theredistribution board 4 previous to the semiconductor elements 6 and 8.In this case, the redistribution board 4 is formed with a thickness tohave enough strength even when the base board 20 is separated orremoved. Alternatively, a material with enough strength is chosen toform the redistribution board 4.

[0082] Next, a description will be given of a fourth embodiment of thepresent invention with reference to FIG. 9. FIG. 9 is a cross sectionalview of a semiconductor device according to the fourth embodiment of thepresent invention. In FIG. 9, those components which are the same asthose corresponding components in FIG. 1 are designated by the samereference numerals, and a description thereof will be omitted.

[0083] The semiconductor device according to the present invention hasthe same structure as the semiconductor device of the above-describedfirst embodiment. However, a structure of a redistribution board 4A isdifferent from the above-described redistribution board 4. That is, asshown in FIG. 9, the redistribution board 4A of this embodiment furtherincludes a columnar metal member 50 (also referred to as a metal pillaror metal post) on the fourth electric conductive layer 40 structuringthe electrode pads. Then, by filling insulating resin 52 between themetal pillars 50, the adjacent metal pillars 50 are insulated and heldseparate from each other.

[0084] A height of the metal pillar is 100 μm, for example. A thicknessof the insulating resin layer is from 70 to 80 μm. By reinforcementeffect of the insulating resin layer 52, the redistribution board 4A hasenough rigidity so as to prevent the deformation of or the damage to theredistribution board 4A.

[0085]FIGS. 10A, 10B, 10C and 10D are cross sectional views forexplaining a manufacturing process of the redistribution board 4A. Inorder to form the metal pillars 50 on the fourth electric conductivelayer 40, after forming the redistribution board 4, a barrier metallayer (an illustration thereof is omitted) of such as Ti, Cr or the likeis formed on the fourth electric conductive layer 40 by a sputterapparatus. Then, as shown in FIG. 10A, a dry film made of a photo resistis attached to the barrier metal layer. Through-holes corresponding thefigure of the metal pillars 50 are formed to the dry film using aphotolithography technology. The thickness of the dry film used is thesame as the height of the metal pillars to be formed. Then, as shown inFIG. 10B, the metal pillars 50 are formed by depositing copper in thethrough-holes of the dry film according to a Cu electrolytic platingmethod.

[0086] After the metal pillars 50 are formed, plated layers 54 areformed on projecting parts of the insulating resin layer 52 as shown inFIG. 11 such that heads of the metal pillars 50 function as electrodepads for mounting the semiconductor elements 6 and 8. It is preferablethat the plated layer 54 have a double layer structure such that thebarrier metal layer made of a Ni plated layer is formed on a partcontacting a surface of the metal pillar 50, and a Pd plated layer or aAu plated layer for improving solder bonding efficiency is formedthereon. A triple layer structure may also be applied such that the Pdplated layer is formed on the Ni plated layer, and the Au plated layeris formed thereon.

[0087] After the plated layer 54 is formed, the dry film is removed asshown in FIG. 10C. Thereafter, as shown in FIG. 10D, the insulatingresin layer 52 is formed by filling the insulating resin between themetal pillars 50. In filling the insulating resin, a method of injectingan epoxy resin in liquid form or a method of filling the epoxy resin bytransfer molding, for example, may be used.

[0088] The semiconductor elements 6 and 8 are mounted on theredistribution board 4A formed as described above by flip chip mountingin the same method as the above-described first embodiment. Besides, theredistribution board 4A is mounted on the package board 2 andincorporated in the semiconductor device shown in FIG. 9.

[0089] As described above, the redistribution board 4A according to thepresent invention has rigidity increased by the insulating resin layer52. Thus, the redistribution board 4A can prevent the deformation ordamage in the manufacturing process of the semiconductor device andimprove a production yield of the semiconductor device.

[0090] Next, a description will be given of a fifth embodiment of thepresent invention with reference to FIG. 12. FIG. 12 is a crosssectional view of a semiconductor device according to the fifthembodiment of the present invention. In FIG. 12, those components whichare the same as those corresponding components in FIG. 9 are designatedby the same reference numerals, and a description thereof will beomitted.

[0091] The semiconductor device according to this embodiment has thesame components as the semiconductor device according to theabove-described fourth embodiment, except that the redistribution board4A is placed upside down. That is, the metal pillars 50 of theredistribution board 4A are connected with the electrode pads of thepackage board 2. The semiconductor elements 6 and 8 are mounted on theelectrode pads made of the electric conductive layer 22.

[0092] A manufacturing method of the semiconductor device according tothis embodiment is the same as the manufacturing method of thesemiconductor device according to the above-described second embodiment,except that the redistribution board 4 is replaced with theredistribution board 4A. Thus, a detailed description thereof will beomitted.

[0093] As the above-described fourth embodiment, the redistributionboard 4A of this embodiment has rigidity increased by the insulatingresin layer 52. Thus, the redistribution board 4A can prevent thedeformation or damage in the manufacturing process of the semiconductordevice, and improve the production yield of the semiconductor device.

[0094] Next, a description will be given of a sixth embodiment of thepresent invention with reference to FIG. 13. FIG. 13 is a crosssectional view of a semiconductor device according to the sixthembodiment of the present invention. In FIG. 13, those components whichare the same as those corresponding components in FIG. 1 are designatedby the same reference numerals, and a description thereof will beomitted.

[0095] The semiconductor device according to this embodiment hasbasically the same structure as the semiconductor device according tothe above-described first embodiment except that a structure of aredistribution board 4B differs from the structure of the redistributionboard 4. That is, as shown in FIG. 13, the redistribution board 4B ofthis embodiment further has micro pins 60 as columnar metal members onthe fourth electric conductive layer 40 structuring the electrode pads.Then, insulating resin 62 is filled between the micro pins 60 so as toinsulate and hold the adjacent micro pins separate from each other.

[0096] A height of a micro pin is 100 μm, for example. A thickness ofthe insulating resin layer 62 is from 70 to 80 μm. By reinforcementeffect of the insulating resin layer 62, the redistribution board 4B hasenough rigidity so as to prevent the deformation of or the damage to theredistribution board 4B.

[0097] As shown in FIG. 14A, the micro pins 60 are formed such thatmetal wires such as gold wires or the like are bonded to the fourthelectric conductive layer 40. Then, heads of the metal wires are cut offso as to obtain a length (height) of 100 μm, for example, in a directionof the thickness of the redistribution board 4. Each of the micro pins60 are provided to the fourth electric conductive layer 40 so as toextend nearly vertically therefrom and not to contact each other.

[0098] When the micro pins 60 are formed, surfaces of the micro pins 60are nickeled by an electroless plating method and gilded. The Ni platingfunctions as the barrier metal, and the gold plating is for improvingthe solder bonding efficiency. Next, as shown in FIG. 14B, insulatingresin such as an epoxy resin or the like fills between the micro pins 60so as to form the insulating resin layer 62.

[0099] The semiconductor elements 6 and 8 are mounted on theredistribution board 4B formed as described above by flip chip mountingin the same method as the above-described first embodiment. Besides, theredistribution board 4B is mounted on the package board 2 and isincorporated in the semiconductor device shown in FIG. 13.

[0100] As described above, the redistribution board 4B according to thisembodiment has rigidity increased by the insulating resin layer 62.Thus, the redistribution board 4B can prevent the deformation or damagein the manufacturing process of the semiconductor device and improve theproduction yield of the semiconductor device.

[0101] Next, a description will be given of a seventh embodiment of thepresent invention with reference to FIG. 15. FIG. 15 is a crosssectional view of a semiconductor device according to a seventhembodiment of the present invention. In FIG. 15, those components whichare the same as those corresponding components in FIG. 13 are designatedby the same reference numerals and a description thereof will beomitted.

[0102] The semiconductor device according to this embodiment has thesame components as the semiconductor device according to theabove-described fourth embodiment except that the redistribution board4B is placed upside down. That is, the metal pillars 50 of theredistribution board 4B are connected with the electrode pads of thepackage board 2. The semiconductor elements 6 and 8 are mounted on theelectrode pads made of the first electric conductive layer 22.

[0103] A manufacturing method of the semiconductor device according tothis embodiment is the same as the manufacturing method of thesemiconductor device according to the above-described second embodiment,except that the redistribution board 4 is replaced with theredistribution board 4B. Thus, a detailed description thereof will beomitted.

[0104] However, it should be noted that the insulating resin layer 62 isnot provided for the redistribution board 4B. Each micro pin standserect by itself. Thus, the micro pin 60 may not contact with theadjacent micro pin 60 when the insulating resin does not fill betweenthe micro pins 60. Accordingly, the under fill material 46 fills betweenthe micro pins 60 after the redistribution board 4B formed on the baseboard 20 is mounted on the package board 2 by soldering via the micropins 60.

[0105] Additionally, when the insulating resin layer 62 is provided, theunder fill material 46 may not be necessary. Further, since the micropins have spring characteristics, the micro pins can stand a heat cycle,shock or the like when the micro pins are connected with the bumps.

[0106] In each of the above-described embodiments, a silicon board isused as the base board 20. However, a board made of other material mayalso be used.

[0107] For example, when a sapphire board is used as the base board 20,the base board 20 can be separated from the redistribution board byirradiation of a laser beam. That is, a thin organic film is formed onthe sapphire board so as to form the redistribution board thereon. Then,the sapphire board is separated from the redistribution board byirradiating the laser beam on the sapphire board and vaporizing theorganic film.

[0108] Additionally, when the base board 20 is formed by copper orcopper alloy, the base board 20 can be removed by dipping only the baseboard 20 in etchant and dissolving the copper or copper alloy. In thiscase, it is preferable to previously perform resin courting so as not toexpose the copper from a wiring layer, a circuit element or the packageboard of the components of the semiconductor device.

[0109] Further, as a method of separating the base board, there is amethod of forming the redistribution board on a water solubleexfoliating layer previously formed on the base board 20. As a materialof the water soluble exfoliating layer, potassium bromide KBr may beused. By forming the redistribution board on the water solubleexfoliating layer formed on the base board 20 and dipping theredistribution board and the base board 20 in water, the water solubleexfoliating layer is dissolved and the base board 20 is separated fromthe redistribution board.

[0110] Additionally, the base board 20 can be dissolved in water to beremoved by forming the base board 20 itself of a water soluble materialsuch as potassium bromide KBr.

[0111] Additionally, in order to separate the base board and theredistribution board (wiring layer) easily, the redistribution board maybe formed by forming a copper (Cu) sputter film on a ceramic board ofsuch as aluminum nitride or the like, and forming the wiring layer orthe like on the Cu sputter layer by photolithography. Since adhesionbetween the Cu sputter film and the ceramic board is weak, the Cusputter layer easily exfoliates from the ceramic board. Afterexfoliating the ceramic board including the Cu sputter film from theredistribution board, the Cu sputter film is removed by the etching, andelectrodes for connecting with the package board and the semiconductorelements are exposed. A forming method of the redistribution board isthe same as the above-described embodiments, and a description thereofwill be omitted.

[0112] The present invention is not limited to the specificallydisclosed embodiments, and variations and modifications may be madewithout departing from the scope of the present invention.

[0113] The present application is based on Japanese priority applicationNo. 2001-335413 filed on Oct. 31, 2001, the entire contents of which arehereby incorporated by reference.

What is claimed is:
 1. A manufacturing method of a semiconductor deviceincorporating a passive element, comprising: a redistribution boardforming step of forming a redistribution board incorporating the passiveelement on a base board; a semiconductor element mounting step ofmounting at least one semiconductor element on an opposite side surfaceof the redistribution board formed on the base board with regard to thebase board; a base board separating step of separating the base boardfrom the redistribution board and exposing an other surface of theredistribution board; and a redistribution board mounting step ofmounting the redistribution board on a package board via electrode padsexposed from the other surface of the redistribution board.
 2. Themanufacturing method of the semiconductor device as claimed in claim 1,wherein the semiconductor element mounting step includes a step offilling between the redistribution board and the semiconductor elementwith an under fill material.
 3. A manufacturing method of asemiconductor device incorporating a passive element, comprising: aredistribution board forming step of forming a redistribution boardincorporating the passive element on a base board; a redistributionboard mounting step of mounting the redistribution board formed on thebase board on a package board via electrode pads exposed from a surfaceof the redistribution board; a base board separating step of separatingthe base board from the redistribution board and exposing an othersurface of the redistribution board; and a semiconductor elementmounting step of mounting at least one semiconductor element on theredistribution board via electrode pads exposed from the other surfaceof the redistribution board.
 4. The manufacturing method of thesemiconductor device as claimed in claim 3, wherein the redistributionboard mounting step includes a step of filling between theredistribution board and the package board with an under fill material.5. The manufacturing method of the semiconductor device as claimed inclaim 1, wherein the base board is made of a silicon wafer, a pluralityof the redistribution boards are integrally formed on said siliconwafer, and the redistribution boards are individualized after the baseboard removing step.
 6. A manufacturing method of a semiconductor deviceincorporating a passive element, comprising: a redistribution boardforming step of forming a redistribution board incorporating the passiveelement on a base board; a base board separating step of separating thebase board from the redistribution board; a semiconductor elementmounting step of mounting at least one semiconductor element on theredistribution board via electrode pads formed on a surface of theredistribution board; and a redistribution board mounting step ofmounting the redistribution board on a package board via electrode padsformed on an other surface of the redistribution board.
 7. Themanufacturing method of the semiconductor device as claimed in claim 1,wherein the redistribution board forming step includes a step of formingcolumnar metal members on the electrode pads of the redistribution boardformed on the other side of the redistribution board with respect to thebase board, and a step of filling between said columnar metal memberswith insulating resin.
 8. The manufacturing method of the semiconductordevice as claimed in claim 1, wherein: the base board is made ofsilicon; and the base board separating step includes a step of removingthe silicon by using etching and grinding together.
 9. The manufacturingmethod of the semiconductor device as claimed in claim 1, wherein: thebase board is made of a sapphire board including a thin organic filmformed on a surface where the redistribution board is formed; and thebase board separating step includes a step of irradiating a laser beamto the thin organic film via the sapphire board and vaporizing the thinorganic film.
 10. The manufacturing method of the semiconductor deviceas claimed in claim 1, wherein: the base board is made of copper orcopper alloy; and the base board separating step includes a step ofdipping the base board in etchant so as to dissolve only the base board.11. The manufacturing method of semiconductor device as claimed in claim1, wherein: the base board includes a water soluble exfoliating layerformed on a surface where the redistribution board is formed; and thebase board separating step includes a step of dipping the base board inwater and dissolving the exfoliating layer in water.
 12. Themanufacturing method of the semiconductor device as claimed in claim 11,wherein the water soluble exfoliating layer is made of potassiumbromide.
 13. The manufacturing method of the semiconductor device asclaimed in claim 1, wherein: the base board is made of a water solubleboard; and the base board separating step includes a step of dipping thebase board in water and dissolving the exfoliating layer in water. 14.The manufacturing method of the semiconductor device as claimed in claim13, wherein the water soluble board is made of potassium bromide. 15.The manufacturing method of the semiconductor device as claimed in claim7, wherein the columnar metal members forming step includes a step ofdepositing copper on the electrode pads in a columnar structure bycopper plating.
 16. The manufacturing method of the semiconductor deviceas claimed in claim 7, wherein the columnar metal members forming stepincludes a step of bonding gold wires with the electrode pads by a wirebonding method.
 17. A redistribution board incorporating a passiveelement comprising: columnar metal members formed on the electrode padsformed on either a front face or a rear face of the redistribution boardand extending in a direction of a thickness of the redistribution boardwith a predetermined length; and an insulating resin layer made ofinsulating resin filled between said columnar metal members.
 18. Theredistribution board as claimed in claim 17, wherein each of thecolumnar metal members is made of a copper plated layer deposited in acolumnar structure.
 19. The redistribution board as claimed in claim 17,wherein each of the columnar metal members is made of gold wire andbonded to the electrode pad by a wire bonding method.
 20. Amanufacturing method of a redistribution board incorporating a passiveelement, comprising: a step of forming a copper sputter film on aceramic board; a redistribution board forming step of forming theredistribution board incorporating the passive element on the coppersputter film; a base board separating step of exfoliating and separatingthe ceramic board from the copper sputter film; and a step of removingthe copper sputter film by etching and exposing electrodes of theredistribution board.